Group
Sam Windross*
Morgan Vondee
Jaynita Patel
Sara Khan
RajPiraveen Rajaratnam
. Alternative Hypothesis
Polymorphism of Capaea nemoralis in grass and shrubland is due to natural selection in the majority of cases, with Genetic Drift and Gene Flow being minor influences. If the hypothesis was seen to be true, then the pressures of selection on the population would have the greater influence on the phenotype. This would be observed by consistent frequency differences of snail shell colours and number Bands between the two habitats.
Null Hypothesis
Polymorphism of Capaea nemoralis in grass and shrub land is not due to natural selection, but Genetic Drift and Gene Flow . If the null hypothesis was proven to be true, then no consistent frequency differences of snail shell colours and number of bands could be observed between the two habitats.
Introduction
Snails are more preferable to study because in their lifetime they only move up to approximately 30 meters, than compared to humans, which have a greater ability to travel (High rates of gene flow) and have a much greater spread across the planet . Therefore to identify the effects of Natural Selection, Genetic Drift and Gene Flow within a population, snails will be our organism of choice. We hope as stated in our hypothesis to see how selection acts within the snail population as apposed to that of drift and gene flow, by observing consistent phenotypic frequency variations between the two habiats of shrub and grass land.
Sampling Method
A transect will be used over the grass land and shrub habitat, with sample area's of 4x4m, at 6 points spaced 25m apart along the transect. This will allow us to attain a large snail sample (representative of the population, and reducing the chance of sampling error), but also allowing us to see observable differences in phenotypes in Capaea nemoralis. We will record the snail shell colour differences and number of bands on the shells in seperate tables in regards to the habitat so that it will be easier to deduce how selection is acting, if at all.
Advantages of our sampling
We are studying two different habitats over a large but diverse area which should give us observable phenotype variations. Taking samples over a transect means we can see whether gene flow has taken effect by observing if there are intermediate phenotypes where the grass and shrubland are in close proximity. We are controlling the effects of other variables like altitude on our sample. Within the sample area's we are using random sampling to attain our results, consequently bias should not affect our results.
Disadvantages
We are only taking 6 samples and are not taking samples from the woodland area, therefore we could make our sample subject to sampling error as we are not representing the whole population. As were using our own judgement to analyse the shell phenotypes, the chance of human error is increased as we can not ensure standardised criteria to sort the shells in band and colour groups.
Sam Windross*
Morgan Vondee
Jaynita Patel
Sara Khan
RajPiraveen Rajaratnam
.
Alternative Hypothesis
Polymorphism of Capaea nemoralis in grass and shrubland is due to natural selection in the majority of cases, with Genetic Drift and Gene Flow being minor influences. If the hypothesis was seen to be true, then the pressures of selection on the population would have the greater influence on the phenotype. This would be observed by consistent frequency differences of snail shell colours and number Bands between the two habitats.
Null Hypothesis
Polymorphism of Capaea nemoralis in grass and shrub land is not due to natural selection, but Genetic Drift and Gene Flow . If the null hypothesis was proven to be true, then no consistent frequency differences of snail shell colours and number of bands could be observed between the two habitats.
Introduction
Snails are more preferable to study because in their lifetime they only move up to approximately 30 meters, than compared to humans, which have a greater ability to travel (High rates of gene flow) and have a much greater spread across the planet . Therefore to identify the effects of Natural Selection, Genetic Drift and Gene Flow within a population, snails will be our organism of choice. We hope as stated in our hypothesis to see how selection acts within the snail population as apposed to that of drift and gene flow, by observing consistent phenotypic frequency variations between the two habiats of shrub and grass land.
Sampling Method
A transect will be used over the grass land and shrub habitat, with sample area's of 4x4m, at 6 points spaced 25m apart along the transect. This will allow us to attain a large snail sample (representative of the population, and reducing the chance of sampling error), but also allowing us to see observable differences in phenotypes in Capaea nemoralis. We will record the snail shell colour differences and number of bands on the shells in seperate tables in regards to the habitat so that it will be easier to deduce how selection is acting, if at all.
Advantages of our sampling
We are studying two different habitats over a large but diverse area which should give us observable phenotype variations.
Taking samples over a transect means we can see whether gene flow has taken effect by observing if there are intermediate phenotypes where the grass and shrubland are in close proximity. We are controlling the effects of other variables like altitude on our sample. Within the sample area's we are using random sampling to attain our results, consequently bias should not affect our results.
Disadvantages
We are only taking 6 samples and are not taking samples from the woodland area, therefore we could make our sample subject to sampling error as we are not representing the whole population. As were using our own judgement to analyse the shell phenotypes, the chance of human error is increased as we can not ensure standardised criteria to sort the shells in band and colour groups.